Data from: Increased natural reproduction and genetic diversity one generation after cessation of a steelhead trout (Oncorhynchus mykiss) conservation hatchery program

Spatial and temporal fluctuations in productivity and abundance confound assessments of captive propagation programs aimed at recovery of Threatened and Endangered populations. We conducted a 17 year before-after-control-impact experiment to determine the effects of a conservation hatchery program for anadromous steelhead trout (Oncorhynchus mykiss) on a key indicator of natural reproduction (naturally produced nests or 'redds'). The supplemented population exhibited a significant (2.6-fold) increase in redd abundance in the generation following supplementation. Four non-supplemented (control) populations monitored over the same 17 year period exhibited stable or decreasing trends in redd abundance. Expected heterozygosity in the supplemented population increased significantly. Allelic richness increased, but to a lesser (non-significant) degree. Estimates of the effective number of breeders increased from a harmonic mean of 24.4 in the generation before supplementation to 38.9 after supplementation. Several non-conventional aspects of the captive rearing program may have contributed to the positive response in the natural population.生产力与丰度的时空波动，会干扰针对受威胁与濒危种群恢复的人工繁育项目评估。本研究开展了一项为期17年的前后对照控制影响实验，以明确针对溯河产卵硬头鳟（Oncorhynchus mykiss）的保育孵化场项目对其自然繁殖关键指标——自然产卵巢（或称"红床（redds）"）的影响。实施增殖补充后的首个世代中，补充种群的产卵床丰度显著提升2.6倍。同期监测的4个未实施增殖补充的对照种群，其产卵床丰度均呈现稳定或下降趋势。补充种群的预期杂合度（expected heterozygosity）显著升高；等位基因丰富度（allelic richness）有所提升，但幅度较小且未达统计学显著水平。繁殖有效种群大小的估计值从增殖补充前世代的调和均值24.4，提升至补充后的38.9。本次人工繁育项目的若干非常规实施细节，或为自然种群产生正向响应的成因。